The present invention relates to a set of wood-type golf clubs having different club-lengths, more particularly to an improvement in a shape of the head of each club viewed from the golfer's eyes capable of providing an easy golf swing without the need to pay a special attraction to the difference in the club-length.
Heretofore, in order to make a golf club easy to swing and use, various attempts and efforts have been made by optimizing mechanical characteristics, e.g. the position of the center of gravity of the head, a moment of inertia of the head, the bending rigidity of the shaft, the bend profile of the shaft and the like so as to improve the golf club itself and/or to adjust it to the target users.
On the other hand, as well known empirically, golf club swing is easily affected by mental factors of the golfer.
In particular, visual impressions of the golf club given to the golfer at address affects golf club swing. More specifically, the golf club swing is largely affected by the shape of the crown portion of the club head to which the golfer pays particular attention.
In Japanese Patent application publication JP-2000-262655A, the assignee of the present invention proposed a golf club, in which three parameters of a golf club head (which are the undermentioned toe-side crown width L1, angle α1, angle α2) are limited within specific ranges.
A golf club having such golf club head is hard to give the golfer at address such impression that the golf club is considerably upright or considerably flat. Accordingly, the golfer can swing with an easy mind, therefore, stable and balanced swing is possible, and a decrease of missed shots may be expected.
Aiming at a further improvement of a golf club in which the club head of JP-2000-262655A is incorporated, the inventor of the present invention studied and recognized the importance of a visual impression of the golf club at address relative to the lie angle and club-length.
As a general rule, in the case of a golf club having a shorter club-length, the lie angle of the golf club becomes larger, and accordingly, a visual impression which the golfer receives from the golf club at address becomes more upright. In general, an upright address puts the golfer in mind of an upright swing, therefore, the golfer tends to worry about the possibility of making a hook shot.
On the other hand, in the case of a golf club having a longer club-length, the lie angle of the golf club becomes smaller, and accordingly, a visual impression which the golfer receives from the golf club at address becomes more flat. In general, a flat address puts the golfer in mind of a flat swing, therefore, the golfer tends to worry about the possibility of making a slice shot.Therefore, golf clubs, especially wood-type golf clubs (namely, driving clubs such as driver, fairway woods and utility woods), which are combined into a golf club set, have to present unified visual impressions controlled such that a golf club having a shorter club-length gives an impression of flatter address than the real lie angle, and a golf club having a longer club-length gives an impression of more upright address than the real lie angle.By controlling the visual impressions in this way, even if the club-length is changed, the golfer can use and swing the club easily without worrying about a slice shot and a hook shot.